The present invention relates to a set of anchoring elements of adjustable type for components of pieces clamping fixtures on a supporting pallet.
This invention relates more precisely to an improvement of the object of the Italian patent application No. 22932 A/87 dated Dec. 10, 1987, which relates to a pallet with an adjustable anchoring system for the preparation of the fixture for clamping a rough piece to be machined with machine tools. (That application corresponds to U.S. patent application Ser. No. 07/278,717, filed Dec. 2, 1988, which was abandoned in favor of continuing U.S. patent application Ser. No. 07/684,507, filed Apr. 15, 1991.)
In particular, in the mentioned patent application, there is disclosed a pallet which comprises one or more supporting faces provided with holes suitably threaded for screwing and unscrewing inside them, and thus for the simultaneous adjustment in height and angular orientation, of respective anchoring elements for active components of the clamping fixture.
The active components of the clamping fixture are associated to the anchoring elements by screwing both directly and through passive intermediate modular elements which merely serve as a connection between the anchoring elements and the active components.
Both the anchoring elements and the intermediate elements of the clamping fixture are internally hollow, to allow the passage of the operating fluid of the active component, fed through appropriate channels inside the pallet.
According to the abovementioned prior art, the two different adjustments, angular and in height, respectively, are not only bound one to the other, but are also executed by devices, such as the anchoring elements, which, in the clamping fixture as a whole, that by means of several intermediate modular elements being positioned one above the other can rise considerably above the pallet's supporting face, are at the lowest level and far from the active components. It is thus difficult in practice to contain within a restricted range of tolerances the angular orientation of the active modular element (be it clamping or supporting), which is at the top of the pile of modular elements, due to errors in machining the threads, to differences in the tightening of the threads, and to any dirt between the abutments.
In addition, in the apparatus disclosed in the above-identified application, when an active component of the clamping fixture which is screwed on an anchoring element is unscrewed, it can occur, due to random differences in the friction between the threads, that the active component actually becomes unscrewed from the anchoring element. It can also occur that the anchoring element becomes unscrewed from the seat in which it is screwed down and remains attached to the active component, thus requiring further and unprogrammed unscrewing and handling operations.